VPI Prime Motor Questions - Noise & Multiple Belts

[bhjazz]

Hm. Well, as much as I was jonesin' for the Sota solution, I'm going to just replace the stock Hurst motor. Sota seems to be in a full-on production schedule right now so retooling for a one-off like my motor pod needs is still weeks out. I can understand that, and can get to it another time. I clicked Buy Now on the Hurst site.

[brimster]

Quick update here... Hurst delivered the motor right on time today. The swap was simple. Really just a matter of removing a few wire nuts, pulling the old motor, and reconnecting and twisting the wire nuts back on. I also replaced the capacitor to stop the power on/off pop while I was in there. This VPI video does a good job explaining the capacitor replacement: https://www.youtube.com/watch?v=0fhDrHJfpmY (thanks bhjazz!)

Here are a few pix I took today: https://photos.app.goo.gl/xVqFb7ps1VkiaCW68

Bottom line: DEFINITELY worth the $99 for the motor and less than an hour of time. I can baaaaaaarely hear the motor running with my ear right up to the motor pod (without music of course). From my listening position I can't hear it at all. I could very clearly hear it from my listening position before making the swap.

[Brf]

I’m glad it worked out for you. I really like the point to point wiring of the older vpi motors. The newer motors have a mini circuit board. Btw, your motor will get even quieter once it breaks in.

[bhjazz]

Quick update here... Hurst delivered the motor right on time today.

Mine finally arrived today, over a week late. Actually had to call (after a few days) and ask if they were going to ship... Oh well, lots going on at casa de bhjazz anyway. Hopefully will squeeze the upgrade in this weekend.

[bhjazz]

brimster: did you move the brass collar on the motor post to your new motor?  I am assembling mine at the moment and see that the new motor does not have one.  Now, the previous version of that motor left the motor post to fine tuning by the user but now I notice that the new version does not allow for that.  Either way, I added mine to help keep dust out. 

Almost there.  I polished the heck out of my pod over the weekend.  Used Flitz and it looks great . If anyone uses Flitz for this, just remember to clean that stuff off *before* it dries, not after.  If you cover the entire pod with Flitz then go back it'll never come off and you'll have to start over.  Ask me how I know...

I can baaaaaaarely hear the motor running with my ear right up to the motor pod. 

EDIT:  For me, this didn't turn out well.  New motor is in and it sounds worse than my original.  From 2 feet away, the new motor sounds like "chuh-chuh-chuh-chuh" and still produces a vibrational hum that I can hear transmitted through my workbench.  Paperwork from Hurst "non returnable" etc.  

Per Brf's post I'll let it run for a while but this is not a good start.

[bhjazz]

Panic averted. Ran it in for a couple of hours and it finally quieted down. I can hear it from about a foot away but that's it.

[tony22]

Whew! That’s good news.

[bhjazz]

Whew! That’s good news.

Kindof! Take a look at my pulley wobble thread. The music gods give and the music gods take away!

[bhjazz]

Long story short: I sent the "new" motor back to Hurst.  (See Pulley Wobble thread if you want to know why.)  For many reasons, Hurst is no longer on my "want to do business with" list.  I reinstalled the original motor back into the Prime motor pod and started various non-scientific noise measurements.  I have a large keyboard/mousepad from amazon that I use with my computer. KTRIO Large Gaming Mouse Pad  I placed the motor pod upright on either my bare desk or on this mousepad for measurements, which were taken by using a vintage Radio Shack sound level meter, using C weighting, and inverted so that the measurement mic was in direct contact with my desk.  The order in which the measurements are presented seems a little confusing so I just put them in order of lowest noise to highest noise. 

baseline, motor off, with computer running........50 dB
pod, plate, no screws, no feet, mousepad..........50 dB
pod, plate, screws, no feet, mousepad...............50 dB
pod, plate, screws, feet, mousepad....................50 dB
pod, plate, no screws, no feet, direct on desk.....55 dB
pod, plate, screws, feet loose, direct on desk .....56 dB
pod, plate, screws, feet snug, direct on desk.......58 dB
pod, plate, screws, no feet, direct on desk..........64 dB

In general, the most likely scenario a user would have (and why I started on this in the first place) would be the 'feet snug' measurement with the pod fully assembled.  My Hana ML was definitely picking up this motor vibration noise and that's why I'm chasing it down.  

I was able to adjust the amount of noise being picked up by moving the motor pod a bit.  The noise varied from 50 to 56 dB, depending on where it was and which foot was closest to the measurement device.  I found that rather interesting, and it sortof throws out that 64 dB measurement.  

My concern about using any mousepad is the likely increase of wow/flutter due to a slightly more unstable base for the motor to operate on.  This pad is fairly thin, so that might not be a worry.  

I am considering some Herbie's Thin Fat Dots as a test to replace my current VPI feet which seem to have hardened a bit over the last few years.  The VPI feet are 13/32" tall (0.4062") while the Dots are 1/8" (0.3175") tall.  0.09" -> 3/32" -ish.  So 1/16th and some change.

EDIT:  Funky math going on.  1/8" is actually 0.125.  Searching for a better solution!

[edwyun]

I tried most of the Herbie's products and Symposium products to try to quiet the Hurst motor on the Prime. Eventually gave up and when to the SOTA BLDC. Much quieter and a no maintenance motor to boot.